Despite near unanimous agreement among climate scientists about global warming, a substantial proportion of Americans remain skeptical or unconcerned. The two experiments reported here tested communication strategies designed to increase trust in and concern about climate change. They also measured attitudes toward climate scientists. Climate predictions were systematically manipulated to include either probabilistic (90% predictive interval) or deterministic (mean value) projections that described either concrete (i.e., heat waves and floods) or abstract events (i.e., temperature and precipitation). The results revealed that projections that included the 90% predictive interval were considered more trustworthy than deterministic projections. In addition, in a nationally representative sample, Republicans who were informed of concrete events with predictive intervals reported greater concern and more favorable attitudes toward climate scientists than when deterministic projections were used. Overall, these findings suggest that while climate change beliefs may be rooted in partisan identity, they remain malleable, especially when targeted communication strategies are used.

Despite overwhelming scientific consensus about climate change, the majority of Americans are not very worried about it. This may be due in part to insufficient understanding of the urgency and seriousness, which may be related among some, to distrust of the scientific community. We test these hypotheses in an experimental study using a broadly nationally representative sample. An explanation of the delay between the reduction of greenhouse gas emissions and cessation of global warming was compared to two control groups, one with basic climate change information and another with no information. Participants also received climate predictions that either included or excluded uncertainty estimates for a 3 × 2 complete factorial design. Results suggest that the delay explanation increased participants understanding of this issue and reduced their agreement with a wait-and-see strategy, especially among conservatives. Moreover, uncertainty estimates increased trust in climate predictions and ratings of climate scientists' expertise and understanding. Uncertainty estimates also increased concern about climate change and the perception of scientific consensus. Although in some cases small, these positive effects were seen across political ideology groups. Public Significance StatementThis experiment demonstrated that targeted scientific explanations can help members of the public understand complex but important climate change issues. It also demonstrated that providing uncertainty estimates along with climate predictions increased trust in the predictions themselves as well as in the climate scientists who produced them and the perception of scientific consensus about climate change.

The four experiments reported here tested the impact of recent negative events on decision-making. Participants were given a virtual budget to spend on crops of varying costs and payoffs that, in some cases, depended on drought conditions. Participants made 46 decisions based on either deterministic or probabilistic seasonal climate predictions. Participants experienced a sequence of droughts either immediately prior to the target trials (recent condition) or early in the sequence (distant condition). In experiment 1, participants made overly cautious crop choices when droughts were experienced recently. Subsequent experiments probed the cognitive mechanisms involved. The effect of recency on overcautiousness was reduced by a midexperiment message, although it did not matter whether the message described a changed or consistent venue and time period. This suggests that overcautiousness was not caused by deducing a climatic trend in the particular area. Instead, we argue that availability—events that are easier to recall are judged to be more likely—was the major cause for increased cautiousness following recent droughts. Importantly, probabilistic predictions attenuated the impact of recency, inspired greater trust, and allowed participants to make better decisions overall than did deterministic predictions. Implications are discussed.